Speakers
Description
Coordination across brain regions is usually summarised by pairwise functional connectivity (FC), which cannot capture how three or more regions act together beyond their pairwise couplings. Pairwise maximum-entropy (Ising) models reproduce many patterns but miss informative interactions. We ask which higher-order structure the data support, using Minimally Complex Models (MCMs): maximum-entropy models that partition regions into communities and keep all interaction orders within each. We turn them into a parameter-free read-out applied across brain states. Each MCM has a closed-form Bayesian evidence whose negative log is asymptotically a description length, so community detection maximises this evidence over partitions: no inferred graph, no preset number of communities. The same quantity yields a per-region description length, a single index of organisation (shorter meaning more compressible coordination). On synthetic networks with a known planted partition, it matches Louvain modularity for purely pairwise interactions and outperforms it for higher-order interactions. Applied to Human Connectome Project resting-state fMRI (~984 young adults; 116 regions), MCMs recover eight communities resembling the resting-state (Yeo) systems plus subcortical regions, differing most in association systems. The population partition is stable (15/116 regions change between sessions), and individual partitions are more reproducible within than across participants (NMI 0.77 vs. 0.68), identifying individuals more accurately than pairwise FC. Across ~720 adults aged 36–100, resting activity requires a longer per-region description with age, becoming less compressible, alongside smaller communities (Pearson r=0.42). In a macaque central-thalamic deep-brain-stimulation dataset, it lengthens under propofol anaesthesia and is partially reversed by thalamic stimulation — most in visual, somatomotor and dorsal-attention networks, least in limbic and subcortical systems. Together, MCMs give a tractable account of higher-order functional organisation and how it changes across the lifespan, with preliminary evidence that the same read-out tracks the loss and recovery of consciousness.
| Preferred Presentation | Oral Presentation |
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